noun

• (figurative) Anything that inspires or motivates, as a spur does a horse.
  "She is a theame of honour and renowne, / A ſpurre to valiant and magnanimous deeds, / Whoſe preſent courage may beate downe our foes, / And fame in time to come canonize us, [...]"
• (geology) A mountain that shoots from another mountain or range and extends some distance in a lateral direction, or at right angles.
• (carpentry) A brace strengthening a post and some connected part, such as a rafter or crossbeam; a strut.
• (architecture) The short wooden buttress of a post.

verb

• (transitive) To prod (especially a horse) on the side or flank, with the intent to urge motion or haste, to gig.
  "Draw, archers, draw your arrows to the head! Spur your proud horses hard, and ride in blood; Amaze the welkin with your broken staves!"
• (transitive) To urge or encourage to action, or to a more vigorous pursuit of an object
  "My desire / (More sharp than filed steel) did spur me forth..."
• (transitive) To put spurs on.
  "to spur boots"
• (intransitive) To press forward; to travel in great haste.

noun

• (electronics) A spurious tone, one that interferes with a signal in a circuit and is often masked underneath that signal.

verb

• (obsolete, dialectal) Alternative form of speer.
  "I haue yonder vncouered a faire girle, Ile be ſo bolde as ſpur her, vvhat might a bodie call her name?"